Abstract: A model and computer program for designing the output stage of a high frequency electronic ballast for a fluorescent lamp. The user specifies a plurality of parameters relating to the operation of the fluorescent lamp, including lamp running power, running voltage, maximum preheating voltage for the lamp, minimum running frequency for the lamp, and an input voltage for the ballast. Based upon these parameters, the computer program calculates the values for various components of the ballast, including the inductor and capacitor of the output stage, such that the preheat frequency is greater than the ignition frequency, the ignition frequency is greater than or equal to the running frequency, the preheat voltage is less than the maximum preheat voltage, and the difference between the preheat frequency and the ignition frequency is greater than about 5 kHz.

Abstract: A circuit for igniting and driving a high ignition voltage load includes first and second series coupled switches arranged in a half bridge circuit having an output node. A step-up transformer has a primary winding that is coupled to the bridge circuit at the output node. A load is coupled to the secondary winding to a return potential. Both the first and second switches are capable of being turned on concurrently for a predetermined interval to supply an ignition voltage across the secondary winding sufficient to ignite the lamp.